1. Field of the Invention
The invention relates to a vehicle and a control method thereof.
2. Description of the Related Art
Japanese Patent Application Publication No. JP-A-2005-147082, for example, describes a vehicle which includes an internal combustion engine, an exhaust gas control catalyst that purifies exhaust gas discharged from the internal combustion engine, and controlling means for performing control that basically suppresses degradation of the exhaust gas control catalyst when a condition is satisfied in which degradation of the exhaust gas control catalyst is promoted, but performs control that suppresses catalyst odor, giving priority to the control that suppresses degradation of the exhaust gas control catalyst, when a predetermined condition is satisfied in which a catalyst odor, i.e., an unpleasant sulfur odor (i.e., the odor of hydrogen sulfide) emanating from the catalyst, is given off that makes an occupant uncomfortable. During control to suppress degradation of the exhaust gas control catalyst in this vehicle, control is performed to suppress degradation of the exhaust gas control catalyst at a high temperature by prohibiting a fuel cut aimed at improving fuel efficiency while slowing down and the like. During control to suppress catalyst odor, control is performed to suppress catalyst odor caused by sulfur buildup in the exhaust gas control catalyst by performing a fuel cut giving priority to suppressing degradation of the exhaust gas control catalyst.
However, in the foregoing vehicle, when the internal combustion engine is shifted to an idle state to suppress degradation of the exhaust gas control catalyst after a fuel cut to suppress catalyst odor has ended, it is necessary to adjust the opening amount of the throttle valve so that the amount of air required for the internal combustion engine to idle in a state appropriate for the engine speed at that time is able to be drawn into the intake pipe. Therefore, in the vehicle described above, the shift into the control to suppress degradation of the exhaust gas control catalyst was not always able to be performed smoothly after control to suppress catalyst odor ended.